Scale (map)

“Map scale refers to the relationship, or ratio, between distance on a map and the corresponding distance on the ground.”

“The great industrial cities in Europe and the United States were vast spectacles…unprecedented in scale and scope and movement in comparison with the cities of a century before.” (Orsi 14) from Crossing the City Line

2 thoughts on “Scale (map)”

  1. Karen Kemp, in Geographic Information Science and Spatial Analysis for the Humanities (pp. 34-35), points out that the way we use scale in our conversations often has the opposite meaning from the way scale is formally defined in the use of GIS or by geographers. She writes,

    One way we often use the term scale is to describe the size of the region we are considering. Thus a large-scale project might mean one that involves a large region, a lot of people and/or a lot of money….

    In contrast, in geography and thus in GISci, there is a technical definition of the term scale that has the completely opposite meaning….scale is measured as the mathematical relationship between the real world and its representation, usually on a map. So scale may be, for example, expressed as “1 cm on the map represents 1000 km on the ground”….Formally this relationship is called the representative fraction and often is stated as a ratio. When speaking of the scale in this manner, then, a small-scale map is one that has a small ratio with the right side being a large number, such as 1:100,000,000. This map would show a very large area and, using the first definition, it would be a large scale map.”

    What Kemp explains here is that a small ratio of map area to land area (e.g., 1 inch = 100,000 feet) could be thought of as a small scale. But in our common language, since it covers a lot of surface area, it’s a large scale map.

    To avoid this, I tend to only speak of “scale” when I’m specifically working to design and print a physical map. Otherwise, I tend to use “large area” to describe a project or features that cover a lot of surface (or zoomed out, perhaps) like a county or a state, and “small area” to describe the opposite, like a neighborhood or a city block (or zoomed in, perhaps).

    Sometimes, line layers like the centers of road or the middles of rivers will look different if they were derived from a large area layer and are then used on a smaller area project. So scale might influence the selection and use of different data. If scale matters, it will nearly always be included in the metadata. Scale may be especially important for aerial imagery, or digitized topographic maps. Larger area will mean less specificity, but also smaller file size.

  2. I really like the way that Kim Knott describes scale in the context of the body in “Spatial Theory and the Study of Religion.” She mentions that “the scale and dimensions of the street and its buildings originate in the human body, its measurements, movements and technologies” (1108). I thought that this quote echoes the idea that humans have the ability to create and, in doing so, they construct meaning. How we assign measurements and interpret their significance are all relative to the human mind and body.

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